1. Field of the Invention
The present invention relates a pulsator for a washing machine, and more particularly to a pulsator for a washing machine which is improved in its structure to enhance washability and to prevent material of items from being tangled.
2. Description of the Prior Art
A conventional washing machine includes a rotating basket with a pulsator at its bottom which is adapted to cause washing water to be whirled to agitate items being washed.
However, since the above-mentioned washing machine carries out washing only by a water vortex caused by the pulsator, the washing machine has drawbacks in that a wash item such as cloth is severely twisted thereby to be damaged easily and is not washed evenly thereby causing washing efficiency to be lowered.
A technique for overcoming the above drawbacks is disclosed in Korean Patent Publication No. 88-2734 (entitled "pulsating device for a washing machine"). A sectional view of an embodiment of a washer incorporating the above pulsating device is shown in FIG. 1.
As shown in the drawing, an outer case 1 is provided therein with a tub 3 suspended by an elastic suspension mechanism and also is provided under the tub 3 with a motor 4, a transmission assembly and a belt transmission mechanism 6.
The tub 3 is provided therein with a rotating basket 7 for washing and spin drying wash items, and the rotating basket is provided at its bottom with a pulsator 8.
The rotating basket 7 is connected to a driving shaft 9 of the transmission mechanism 5, and the pulsator 8 is connected to a pulsating shaft (not shown) of the transmission mechanism 5 via a reduction mechanism 10 provided at a bottom of the rotating basket 7.
The transmission mechanism 5 has a clutch mechanism 11 by which a rotating force of the motor 4 is transmitted to the pulsating shaft and the driving shaft 9 or is cut off to rotate the pulsator 8 in a washing mode and to rotate the rotating basket 7 together with the pulsator 8 in a spin-dry mode. The pulsator 8 is adapted to repeat forward and reverse rotation, for example, the pulsator is rotated forwardly at 3 turns and then reversely rotated 3 turns and the procedure is repeated.
Referring to FIG. 2, there is shown a plan view of the pulsator. As shown in FIGS. 1 and 2, a base disk portion 12 is constructed as having a disk shape covering a substantial bottom area of the rotating basket 7 and is provided at its upper surface with four blade portions 13 extended radially and upward. Provided at the center portion of the base disk portion 12 is a center post portion 14 which protrudes upward beyond the blade portions 13.
The center post portion 14 is provided at its upper end with a shaft connecting portion 15 aligned with the center of base disk portion 12, and the shaft connecting portion 15 is connected to an output shaft 10a of the reduction mechanism 10.
As again shown in FIG. 2, the center post portion 14 has an elliptic shape in horizontal section the center of which is eccentrically positioned from the rotating center of the base disk portion 12 (the center of the shaft connecting portion 15).
The above-constructed pulsating device for a washing machine can enhance with complexity of the agitated water current as compared with a conventional vortex thereby to increase washing efficiency and also can carry out a shaking wash, a rubbing wash, a pressing wash and reverse of cloth by means of a force of the center post. Accordingly, the device can enhance agitating efficiency and washing efficiency.
However, although the above pulsating device for a washing machine may enhance washing efficiency, it has a limited ability for increasing the complexity of water current and thus a limited ability for increasing washing efficiency. That is, when the amount of the above-mentioned eccentricity of the center post 14 is too much, a load applied to the motor is increased. Conversely, when the amount of eccentricity is to small, water current is simplified (less complex) thereby decreasing washing efficiency.